From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: "Rafael J. Wysocki" To: Bjorn Helgaas Cc: Takao Indoh , Vivek Goyal , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "open list:INTEL IOMMU (VT-d)" , "kexec@lists.infradead.org" , "ishii.hironobu@jp.fujitsu.com" , Don Dutile , "Sumner, William" , "alex.williamson@redhat.com" , Haren Myneni , "linux-acpi@vger.kernel.org" Subject: Re: [PATCH v2] PCI: Reset PCIe devices to stop ongoing DMA Date: Wed, 31 Jul 2013 23:23:28 +0200 Message-ID: <1699397.FXoFYIGzbk@vostro.rjw.lan> In-Reply-To: References: <1368509365-2260-1-git-send-email-indou.takao@jp.fujitsu.com> <51F85BCC.2070103@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-acpi-owner@vger.kernel.org List-ID: On Wednesday, July 31, 2013 03:08:03 PM Bjorn Helgaas wrote: > [+cc Rafael, linux-acpi] > > On Tue, Jul 30, 2013 at 6:35 PM, Takao Indoh wrote: > > > On x86, currently IOMMU initialization run *after* PCI enumeration, but > > what you are talking about is that it should be changed so that x86 > > IOMMU initialization is done *before* PCI enumeration like sparc, right? > > Yes. I don't know whether or when that initialization order will ever > be changed, but I do think we should avoid building more > infrastructure that depends on the current order. > > Changing the order is a pretty big deal because it's a lot more than > just the IOMMU. Basically I think we should be enumerating ACPI > devices, including the IOMMU, before PCI devices, but there's a lot of > legacy involved in that area. Added Rafael in case he has any > thoughts. Well, actually, I'm not really familiar with IOMMUs, sorry. I do think that initializing IOMMU before PCI enumeration would be better, however. At least if the ordering should be the same on all architectures, which I suppose is the case, that's the one I'd choose. Thanks, Rafael